A shutter base of this kind has been fabricated by stamping a plate from a metal material, such as brass or an aluminum alloy, and then coupling shafts, spacers, poles, etc. to the plate by caulking. The shafts are used to support driving members and other linkages. These shafts, spacers, poles, etc are typically fabricated by machining.
In recent years, cameras have been manufactured in smaller sizes and lighter weights. Also, reductions in the cost of manufacturing cameras are continually strived for. With these trends, the shape of the body of each camera has been made simpler. Accordingly, it has become impossible to neglect harmful light rays which pass from the sides of the shutter into the shutter opening. This problem has become more acute with the use of more sensitive films. In an attempt to satisfy the foregoing requirements, it has been proposed to make focal-plane shutter bases from plastics. However, plastics have not been put into practical use because they do not provide sufficient mechanical strength.